DESCRIPTION: (Applicant Abstract) We are submitting a continuation request to extend the period of follow-up from 12 to 36 months in a study of the onset course, and patterns of service use of men and women seeking crisis treatment for an episode of DSM-IV psychotic disorder accompanied by drug use. It is designed to distinguish between substance-induced psychosis and primary psychosis that co-occurs with drug use. Four hundred subjects who present to the psychiatric emergency service with psychotic symptoms of recent onset associated with the use of drugs are being evaluated over a five-week intake period, contacted monthly for service use data, and interviewed again at six month intervals over a three year follow-up period. Diagnostic data include the intake facility diagnosis, research diagnoses at intake and at six-month intervals, and yearly "LEAD" diagnoses based on the multiple sources of data gathered over the three-year follow-up period. Elaboration of specific aims probe the long-term outcome of substance-induced psychoses and primary psychoses that co-occur with substance use in relation to antecedent characteristics assessed at intake, course of psychosis and substance use disorder, and the match between diagnosis and type of treatment for substance abuse. Outcome will be studied in terms of engagement in treatment, number of psychotic episodes, patterns of drug use, social and occupational functioning, service use, family and social support, residential stability, violent behavior, and HIV risk behavior and serostatus. Widespread abuse of substances known to cause psychotic symptoms has produced neuropsychiatric disorders that place new demands on the substance abuse and mental health service systems. Psychotic patients who use drugs have a need for treatment of their substance abuse. The diagnostic distinction between a substance-induced psychosis and a primary psychosis that co-occurs with drug use is of critical importance in planning for appropriate treatment. Long-term follow-up data, currently lacking, are needed to clarify the most appropriate assessment procedures, the significance of diagnostic distinctions made at various points in time, and the course of psychosis and patterns of substance use. Greater knowledge of the long-term course and outcome of these disorders may lead to more appropriate matches to treatment for substance use, and may uncover unmet needs for services.